A machine tool (a conventional workpiece machining apparatus) is provided with a plurality of modules each installed on a bed of the machine tool and including a main spindle for gripping a workpiece and a tool holder for holding a tool for machining the workpiece gripped by the main spindle. Such a conventional machine tool machines the workpiece while transferring the workpiece among the plurality of the modules (see WO2010/004961 A1).
Further, a conventional control device includes a plurality of control systems for controlling a driving shaft of the machine tool and operates the machine tool by executing a multi-system program. Here, the multi-system program of the conventional control device includes a plurality of machining programs corresponding to the plurality of control systems respectively. With the conventional control device, therefore, each of the control systems is assigned to each of the modules, and each of the modules is controlled by executing a machining program of the corresponding control system assigned to the module.